In order to improve capability of detection, infrared optical system, in a complex electromagnetic environment, is
required to have high sensitivity and dynamic range. The value of dynamic range shows the range of infrared radiation
detected by infrared optical system. The wider dynamic range of infrared optical system, the more objective information
detected, and this helps to analyze and identify targets more. Based on the definition of dynamic range of infrared optical system, a method of testing and data processing of dynamic range is described in detail. And it is proved to be feasible and suitable for testing the dynamic range of infrared optical system with wide Field of View.